Drying of liquid developed copy sheets in a copying machine

ABSTRACT

A flow of drying air in the direction of movement of and under successive individual sheets is provided as they leave development means after exposure in a copymaking machine and from which the exposed sheets are received and free liquid removed before the sheets are engaged by the air. The arrangement is such that the sheets are floated to a copy sheet receptacle.

United States Patent Tiger et al.

[54] DRYING OF LIQUID DEVELOPED COPY SHEETS IN A COPYING MACHINElnventors: Emil Tiger, Highland Park; Erskine G.

Corman, Forest Park; Kenneth R. Reick, Downers Grove, all of I11.

Assignee: Sunbeam Business Equipment Co., Addison, L

Filed: July 24, 1969 Appl. No.: 844,373

Related US. Application Data Division of Ser. No. 665,447, Sept. 5,1967, Pat. No. 3,476,479, which is a division of Ser. No. 410,549, Nov.12, 1964, Pat. No. 3,345,926.

1m. 01. ..G03g 13/10, 003g 15/10 Field of Search ..95/89, 94; 355/10,14, 27, 355/28, 29

Primary Examiner-Samuel S. Matthews Assistant Examiner-Michael L.Gellner Attorney-Hill, Sherman, Meroni, Gross & Simpson [57] ABSTRACT Aflow of drying air in the direction of movement of and under successiveindividual sheets is provided as they leave development means afterexposure in a copymaking machine and from which the exposed sheets arereceived and free liquid removed before the sheets are engaged by theair. The arrangement is such that the sheets are floated to a copy sheetreceptacle.

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INVENTOR. 5071/ 7798/" Erskme 6? German lien/76f E. Ee/ck W MATTORNEYSDRYING F LIQUID DEVELOPED COPY SHEETS IN A COPYING MACHINE Thisapplication is a division of our copending application Ser. No. 665,447,filed Sept. 5, 1967, now US. Pat. No. 3,476,479 issued Nov. 4, 1969,which was a division of our application Ser. No. 410,549, filed Nov. 12,I964, now US. Pat. No. 3,345,926, issued Oct. 10, 1967.

The present invention relates to the drying of liquid developed copysheets in a copying machine, and is more particularly concerned withsuch drying of copy sheets especially suitable for electrophotographiccopying machines employing liquid development of the copy sheets.

Among the objects of the present invention is the provision of new andimproved means for drying copy sheets as they are delivered from aliquid development means and in a manner to facilitate movement of thesheets away from the development means to a collection or receivingpoint.

Another object of the invention is to provide a new and improved methodof and means for drying copies after emergence from a liquid toner bathin a copying machine.

A further object of the invention is to provide new and improved meansfor transporting the finished copy in a copying machine.

Other objects, features and advantages of the invention will be readilyapparent from the following description of certain preferred embodimentsthereof, taken in conjunction with the accompanying drawings, althoughvariations and modifications maybe effected without departing from thespirit and scope of the novel concepts of the disclosure, and in which:

FIG. 1 is a vertical longitudinal sectional elevational schematic viewthrough the front portion of a machine'embodying features of theinvention;

FIG. 2 is a continuation of FIG. 1 showing the rear portion of themachine;

FIG. 2A is an enlarged fragmentary detail view of that portion of FIG. 2indicated by the circle IIA;

FIG. 3 is a sectional elevational detail view taken substantially on theline IIIIII of FIG. 2; and

FIG. 4 is an electrical diagram of the control circuitry of the machine.

An enclosing cabinet 5 houses the machine and includes a base wall 7, afront wall 8, respective opposite sidewalls 9, a rear wall and a topwall 11. Within the housing suitable reinforcing and supporting framestructure is provided including various transverse frame bars 12.

In the front upper portion of the housing 5 are provided means forscanning a document original to be copied. For this purpose, the frontwall 8 is inset a short distance adjacent to the top of the cabinet andan upwardly facing receiving ledge 13 is provided on which documents arehand fed into a receiving throat 14 leading to the nip of a driven feedroller 15 and a coacting idler roller 17 by which the document is fedrearwardly through a guide passage between narrowly spaced upper andlower passage plates 18 and 19 which guide the document to the nip of asecond driven feed roller 20 and a coacting idler roller 21 set todivert the infed document diagonally downwardly and rearwardly through apassage defined by an upper guide plate 22 and a closely adjacentlyspaced lower guide plate 23 leading the advancing document into the nipof a driven feed roller 24 and an idler roller 25 set to bend theleading edge of the document to travel about the driven roller 24 asguided by a semicylindrical closely spaced guide bracket 27. Thence, theleading edge of the document passes into the nip of the driven roller 24and an idler roller 28 by which the document is directed diagonallyupwardly and forwardly in reverse to the passage between the plates 22and 23 and parallel thereto past a scanning aperture 29 defined by alower document guiding and aperture bracket 30 and an upper spaceddocument guiding and aperture bracket 31. Cooperative in documentguiding relation with the brackets 30 and 31 is a guide and backingplate 32 which extends across the scanning aperture 29 and affords anopaque backing for the document.

Beyond the guide bracket 31, the document is guided into the nip of thedriven roller 20 and a cooperating idler roller 33 from which thedocument is guided into a substantially horizontal plane forwardly by anupper guide plate 34 and a lower guide plate 35 defining a guide passagetherewith leading to the nip of the driven roller 15 and a lower idlerfeed roller 37 by which the copied document is delivered into andthrough an exit passage 38 defined between spaced upper and lower plates39 and 40 and located adjacently below the infeed or entry ledge 13 inthe uppermost front portion of the cabinet.

Illumination of the document as it passes the scanning aperture 29 iseffected by means comprising a high-intensity tubular lamp 41 mountedwithin a channel-shaped parabolic reflector 42 located below thehorizontal portions of the docu ment transport system and projectinginto the scanning aperture above a reflection path from the aperture toa scanning mirror 43 mounted on one of the cross bars 12 below andforwardly relative to the reflector 42. As indicated schematically bylight ray lines L, concentration of scanning illumination of the exposedportion of the document as it passes across the aperture 29 is enhancedby reflecting surfaces provided by respective flanges 44 and 45 onlthebrackets 30 and 31, respectively.

Light shielding of the scanning area is afforded by the front wall 8,the document guide passage panels 35 and 40 at the top, by respectiveopposite vertical side panels 47, a rear shielding panel 48 and a bottomshielding panel 49. At its lower end, the front wall 8 is attached tothe front cross bar 12 on which the reflecting mirror 43 of the scanningoptical system is mounted and which bar is spaced substantially abovethe bottom wall 7. Attachment of the front end of the bottom shieldingpanel 49 is also to the front transverse frame bar 12.

Attachment of the upper edge of the rear shielding panel 48' is to theaperture and reflector bracket 30 which, for this purpose, is providedwith a longitudinal downwardly and forwardly opening groove 50 alongsidethe flange 44 and into which the edge portion of the panel 48 is fitted.At its lower end, the panel 48 is attached to the adjacent transverseframe bar 12 which is located in rearwardly spaced relation to themirror 43 and in upwardly spaced relation to the bottom shielding panel49.

Between the bottom panel 49 and the overlying spaced frame bar 12 ismounted a lens supporting bracket structure 51 carrying image projectinglens means comprising an assembly including a barrel 52 and aligned forreceiving from the scanning mirror 43 the image of the document passingthe illuminated scanning aperture 29 and focusing such image generallyrearwardly and in this instance slightly upwardly into an exposureaperture 53 located in about the center of the rear portion of thechamber within the cabinet housing 5. Mean providing a'projection tunnelfrom the lens or objective assembly 52 to the exposure aperture 53comprise a rearward extension of the lower panel 49 and an upper tunnelpanel 54 having its forward end attached to the transverse frame bar 12contiguous to the lens assembly.

Supporting the rear ends of the tunnel-forming extension of the lowerpanel 49 and of the tunnel panel 54 are transverse parallel, coextensivespaced exposure aperture defining bracket members 55 which are desirablyconstructed identically as the scanning aperture defining and panelsupporting bracket 30. The bracket bars 55 have aperture-definingrespective flanges 57 and alongside such flanges respectivepanel-receiving grooves 58 within which the adjacent edge portions ofrespectively the tunnel-defining panels 49 and 54 are engaged.

A copy sheet magazine including a magazine receptacle 60 is mounted inthe housing 5 above the document transport assembly and extendingrearwardly under the top wall 11 to a suitable position rearwardly abovethe projection tunnel and the exposure aperture 53. Access into the copysheet supply magazine is conveniently through a hinged cover 61 formingpart of the top wall. Successive copy sheets are fed from a stack in themagazine receptacle 60 by frictional feed roller which lies on top ofthe rear portion of the stack and is carried by one or more arms 63 of apivotally mounted roller supporting frame pivoted at its rear endportion on a horizontal axis pivot 64. This feed roller is driven by anelectrical motor 65 mounted under the rear portion of the top wall 11,alongside the right-hand inner housing vertical frame panel 47 and has adrive shaft 67 coupled with the feed roller by a drive pulley 68 on theshaft with a flexible driving element belt 69 trained thereover and overa similar driving pulley (not shown) carried corotatively by one endportion of the shaft carrying the roller 62 and by which the feed rolleris driven counterclockwise as viewed in FIG. 2. Adjustable side grippingmeans 70 engage the sides of the stack of sheets in the magazine andresist feeding of multiple sheets.

From the magazine 60, each of the copy sheets 59 is directed into aconverging guide throat 71 extending rearwardly and then downwardly toguide the feed copy sheet into a plane past the exposure aperture 53. Atthe lower end of the guide throat the copy sheet is directed to the nipof a driven feed roller 72 and a coacting idler roller 73 which thenassume onward feeding transportation of the copy sheet.

For electrophotographic copying, the copy sheets 59 are of theelectrophotographic type such as a paper backing having a photosensitivecoating comprising zinc oxide or the like plus a binder. Such materialis adapted to take an electrostatic charge on passing through a chargingdevice 74 including corona discharge wires 75 located alongside andacross the path of travel of the copy sheet, and preferably on bothsides of such path. This corona charging device 74 is located as closeas practicable to the downstream side of the feed rollers 72, 73 andadjacent to the upstream side of a set of feed rollers comprising adriven roller 77 and a coacting idler roller 78 to the dielectric nip ofwhich the charged copy sheet is fed from the charging device.Immediately following the feed rollers 78 and 77, the charged copy sheetpasses the exposure aperture 53 with the sensitized surface of the sheetexposed to the image projected from the scanned document concurrentlypassing the scanning aperture 29. Backing the copy sheet across theaperture 53 is a plate 79 cooperating in appropriately spaced relationwith the aperture-defining brackets 55 to provide a passage and guidefor the sheet. Immediately on leaving the exposure aperture guidepassage, the exposed sheet is engaged by a set of dielectric transportrollers comprising a driven roller 80 and a coacting idler roller 81.

Immediately on leaving the transport roller 80 and 81, the exposed sheetis transported through image developing and fixing means comprising areceptacle 82 in the form of a troughlike tray opening upwardly andhaving an elevated rear curved lead-in edge 83 adjacent to the dischargeside of the rollers 80 and 81. Within the developer tray 82, the copypaper is guided in an arcuate path downwardly and forwardly and thengenerally upwardly and forwardly and passes through a developer bath 84comprising a suitable liquid vehicle and toner or developer particles.This developer bath or solution is maintained in constant circulationfrom a supply tank 85 below the tray 82 and from the bottom of which thesolution is pumped by a pump unit 87 through a riser duct 88 into thebottom of the tray and returns through an overflow duct 89 leading fromthe tray into the tank. Driving of the pump unit 87 is by a pump motor90 which may be conveniently mounted above a top cover 91 for the tank85 on posts 92 and has a drive shaft 93 extending down into drivingrelation with the pump unit 87.

On leaving the toner bath 84, the developed copy sheet is directed bythe curved guide wall of the tray 82 into the nip of transport andsqueeze rollers comprising a driven roller 94 and a coacting idlerroller 95 by which the surplus solution is squeezed from the copy sheetand the sheet is transported away from the developer tray. Solutionsqueezed from the sheet is received in a drip trough 97 under the roller94 and comprising a forward extension on the tray 82. A drain duct 85.Access to the developer tank and tray assembly may be had through thebackwall 10 of the housing through a removable panel or door 99.

On leaving the squeezing and transport rollers 94, the still damp andnow fully developed copy sheet is propelled generally forwardly and isdeflected downwardly and forwardly by the overlying tunnel extension ofthe shield 49 which is desirably provided with longitudinal downwardlyprojecting spacer ribs 100 to avoid possible adherence of the damp copysheet thereto. Underlying the path of movement of the copy sheet isdischarged from the rollers 94 and 95 is a downwardly and forwardlyextending guide plate 101 providing a discharge chute leading to areceiving area in the lower forward portion of the housing between thebottom wall 7 and the top side of the chute provided by the downwardlyfacing wall of the light tunnel, herein the shield panel 49, and readilyaccessible at the front of the machine below the mirror 43 for removalof the finished copies.

Means are provided for accelerating movement of the discharged copysheets down the ramp into the receiving hopper and for simultaneouslydrying the clamp sheets. In a highly desirable manner, this is effectedby providing an air cushion under the sheets as they travel down thechute or ramp 101 whereby to effect an antifriction air layer under thesheets to float the sheets into the receiving hopper. For acceleratingdrying of the sheet such air is desirably heated. Economically, thesource of waste heat created by the scanning lamp 41 is utilized for thepurpose. Therefore, an air circulation suction port 102 is provided inone of the vertical frame panels 47, herein the one located at the leftside of the cabinet adjacent to the reflector trough and of a size topass a substantial volume of air therethrough from the scanning chamber.Leading from the suction port 102 downwardly and rearwardly between theframe panel 47 and the adjacent sidewall 9 is a suction duct 103extending downwardly and rearwardly and communicating with a horizontalsuction tube 104 which opens into the intake of a rotary squirrel cageblower 105 located to discharge toward louvers 107 opening through thelower end portion of the chute plate 101 and through a vertical downwardpartition extension 108 of the chute plate defining the rear of thereceiving hopper area. Through this arrangement, cooling air iscirculated through the scanning chamber and over and past the lamp 41and the reflector 42 as a result of suction developed by the blower 105and the heated air is blown through the louvers 107 to provide thedischarged copy sheet propelling and drying air movement and indicatedby the directional arrows in FIG. 2A. After the trailing edge of thecopy sheet passes beyond the lower end of the chute plate 101, air blownthrough the louvers 107 in the plate 101 as well as the air issuingthrough the louvers 107 in the vertical partition 108 acts on the upperside of the sheet to force it downwardly onto a receiving plate 109. Itwill be observed that the series of louvers 107 terminates a substantialdistance above the innermost end of the receiving plate 109 so that asthe rear end of the copy sheet drops below the series of louvers,press-down action of the air pushing through the louvers acceleratespiling of the sheet toward the receiving plate. To facilitate removal ofcopy sheets from the discharge receptacle, a retractable plate structure110 may be provided.

Driving of the blower 105 as well as all of the several documentoriginal and copy sheet transport rollers is effected by a singleelectrical motor 111 having a drive shaft 112 extending therethrough andon one end portion of which the blower 105 is directly corotativelymounted. The opposite end portion of the shaft 112 is suitably coupledwith a suitable speed reducing gear unit 113 supporting the motor andcarried by the adjacent side vertical frame panel 47. A drive shaft 114of the reduction gear unit carries corotatively a driving wheel whichmay comprise a sprocket 115 over which is trained a flexible drivingcoupling member comprising a chain 117 running drivingly over respectivesprocket gears on the several driven transport rollers. At a suitablepoint, as in the span of the drive 98 returns collected solution fromthe trough 97 into the tank 75 chain 117 between the driven rollers 24and 72, a slack takeup idler 118 is desirably provided. Through thisarrangement, all of the driven rollers travel at the same speed in boththe document original transport system and the copy sheet transportsystem.

An electrical circuit is provided (FIG. 4) for controlling operation ofthe machine. For this purpose, the circuit includes customary powerleads 119 adapted to be connected with a suitable source of electricalcurrent. Directly connected in this circuit are the pump motor 90 andthe blower and chain 1 drive motor 111, so that when a master controlswitch 120 is closed the document and copy sheet transport systems andthe blower 105 run continuously and the liquid toner 84 is in constantcirculation for optimum toner distribution throughout the liquid vehicleand for continuous replenishment of the toner supply in the developmenttray. Conveniently the master switch 120 is mounted on the front of thecabinet (FIG. ll) for suitable on" and off manipulation.

Operation of the copy sheet feed drive motor 65 is under control of thedocument to be copied and of the successive copy sheets and the copysheets control operation of the lamp 41 and the charging device 74. Forthis purpose, the lamp 41, the feed motor 65 and a power pack 121 forthe corona discharge device are connected in the electrical power supplycircuit under the control of various trip or micro switches including anormally open switch 122 which is mounted on or adjacent to the documentguide plate 22 between the document transport rollers 21 and 25 and hasa trip arm ll23 disposed in the path of the in-travelling document whenit enters the flow or guide path between the plates 22 and 23. Trippingof the actuator 123 by the document, closes the switch 122 and therebycloses the energizing circuit through the feed motor 65 whereby one ofthe copy sheets 59 is fed into the copy sheet transport system andactuates a two-way control switch 124 (FIGS. 2 and 4) having a trip arm125 disposed in the path of the copy sheet between the transport rollers72, 73 and the corona charging device 74. This breaks the circuitthrough the feed motor 65 and closes a circuit to energize a relay 127closing normally open switch contacts 128 and completing an energizingcircuit through the lamp 41 and the corona discharge power pack 12]. Theswitch 124 remains under the control of the copy sheet until thetrailing end of the copy sheet leaves the transport rollers 80 and 81,by provision of a second actuator 129 extending into the path of thesheet on the exit side of the transport rollers 80 and 81 and just abovethe lead-in lip 83 of the developer tray.

Promptly upon release of the switch'actuator 129 from the charged copysheet, the switch 124 automatically returns to its feed motor circuitclosing condition and the feed motor 65 is energized to feed the nextsucceeding copy sheet from the magazine into the guide throat 71. At theexit from the guide throat and immediately before the copy sheettransport rollers 72 and 73 a trip arm or actuator 130 of a normallyclosed switch 131 is tripped by the leading edge of the newly fed copysheet and opens the switch 131 to open the feed motor circuit anddeactivate this motor until the shunt around the switch 131 is againclosed by closing of the control switch 122 by a document to be copied.For synchronization the distance from the tripping position of the triparm 123 of the switch 122 to the near side of the scanning aperture 29in the path of travel of the document is identical with the distancefrom the engagement position of the trip arm 130 of the control switch131 and the near edge of the exposure aperture 53. Thereby, automaticsynchronization of documents to be copied and corresponding copy sheetsis attained for high-speed operation. In practice virtually as soon as adocument to be copied is returned through the exit 38, the finished copyis delivered into the receiving hopper in the lower front of the machineand in a sufficiently dry condition to be handled immediately.

An illumination intensity modulating shutter 132 is pivotally mountedadjacent to the scanning mirror 43 and is operable from the front of themachine by a lever 133.

We claim:

E. An arrangement for handling light-sensitive copy sheets which havebeen exposed to light to provide a latent image thereon, comprising:

a receptacle for liquid developer solution;

means for transporting the sheets through the developer solution andthen moving the developed sheets onward while still damp towards areceiving point with one face generally downward;

means for providing drying air under and toward the downward faces ofthe damp sheets as they move from the receptacle to the receiving pointand in sufficient volume to substantially dry the sheets for immediatehandling upon arrival at the receiving point; and

means for directing air downwardly against the sheets after they havereached the receiving point.

2. An arrangement according to claim 1, said means for directing airdownwardly comprising a series of downwardly directed louvers disposedat a height such that the downwardly directed air strikes the trailingend portions of the sheets as they pass thereby.

3. In a machine for making copies and including means for exposure of acopy sheet:

means for liquid development of the exposed copy sheet;

means receptive of the exposed copy sheet from the liquid and operativeto remove free liquid from the copy sheet; upwardly facing downwardlysloping guide means defining a space thereunder and having openings andalong which the sheet moves from said free-liquid-removing means withone face of the sheet confronting the guide means while movingtherealong; and means mounted in said space under said guide means andoperative to effect a flow of drying and propelling air through saidguide means under the sheet and against said one face.

4. A machine according to claim 3, including a lamp in said exposuremeans, and a duct leading from the vicinity of said lamp and conductingair heated by the lamp to said means mounted under said guide means.

5. A machine according to claim 3, in which said guide means comprises aperforated plate having (a surface extending obliquely downwardly andfacing generally away from the free-liquid-removing means and having) aplurality of air openings directed (generally away from the removingmeans so that the drying air is also directed generally away from theremoving means) to float the sheets along said plate (surface and awayfrom said removing means).

6. An arrangement for handling light-sensitive copy sheets which havebeen exposed to light to provide a latent image thereon, comprising:

a receptacle for liquid developer solution;

means for transporting the sheets through the developer solution andthen moving the developed sheets onward while still damp towards areceiving point with one face generally downward;

a perforated guide plate having a space thereunder and providing a rampsloping downwardly and away from said receptacle toward said receivingpoint; and

means in said space under said plate for driving drying air toward andto issue through said plate and impinge the downward faces of the dampsheets as they move from the receptacle to the receiving point along theplate.

7. An arrangement according to claim 6, in which said means for drivingdrying air comprises a blower mounted under the plate and operative todrive the air therethrough.

8. An arrangement according to claim 7 including a motor for drivingsaid blower and said transport means.

9. In a machine for making copies and including means for exposure of acopy sheet:

means for development of the exposed copy sheet;

means for guiding the developed copy sheet to a receiving point; and gmeans for directing air downwardly against the trailing end portion ofsaid sheet to enhance stacking of the sheet at said receiving point.

10. In a machine according to claim 9, a vertical plate portion overwhich the sheet is advanced to said receiving point, and generallydownwardly directed louvers in said plate portion through which the airis directed.

11. In a machine for making copies and including means for exposure of acopy sheet;

means for liquid development of the exposed copy sheet;

squeeze rollers operative to remove free liquid from the copy sheet asit leaves the liquid development means and impelling the sheet toward areceiving point;

means defining a guideway flaring from said rollers generally downwardlyand toward the discharge point;

means for driving air through said guideway means onto a said plate anddriving the air through said louvers.

1. An arrangement for handling light-sensitive copy sheets which havebeen exposed to light to provide a latent image thereon, comprising: areceptacle for liquid developer solution; means for transporting thesheets through the developer solution and then moving the developedsheets onward while still damp towards a receiving point with one facegenerally downward; means for providing drying air under and toward thedownward faces of the damp sheets as they move from the receptacle tothe receiving point and in sufficient volume to substantially dry thesheets for immediate handling upon arrival at the receiving point; andmeans for directing air downwardly against the sheets after they havereached the receiving point.
 2. An arrangement according to claim 1,said means for directing air downwardly comprising a series ofdownwardly directed louvers disposed at a height such that thedownwardly directed air strikes the trailing end portions of the sheetsas they pass thereby.
 3. In a machine for making copies and includingmeans for exposure of a copy sheet: means for liquid development of theexposed copy sheet; means receptive of the exposed copy sheet from theliquid and operative to remove free liquid from the copy sheet; upwardlyfacing downwardly sloping guide means defining a space thereunder andhaving openings and along which the sheet moves from saidfree-liquid-removing means with one face of the sheet confronting theguide means while moving therealong; and means mounted in (a) said spaceunder said guide means and operative to effect a flow of drying andpropelling air through said guide means under the sheet and against saidone face.
 4. A machine according to claim 3, including a lamp in saidexposure means, and a duct leading from the vicinity of said lamp andconducting air heated by the lamp to said means mounted under said guidemeans.
 5. A machine according to claim 3, in which said guide meanscomprises a perforated plate having (a surface extending obliquelydownwardly and facing generally away from the free-liquid-removing meansand having) a plurality of air openings directed (generally away fromthe removing means so that the drying air is also directed generallyaway from the removing means) to float the sheets along said plate(surface and away from said removing means).
 6. An arrangement forhandling light-sensitive copy sheets which have been exposed to light toprovide a latent image thereon, comprising: a receptacle for liquiddeveloper solution; means for transporting the sheets through thedeveloper solution and then moving the developed sheets onward whilestill damp towards a receiving point with one face generally downward; aperforated guide plate having a space thereunder and providing a rampsloping downwardly and away from said receptacle toward said receivingpoint; and means in said space under said plate for driving drying airtoward and to issue through said plate and impinge the downward faces ofthe damp sheets as they move from the receptacle to the receiving pointalong the plate.
 7. An arrangement according to claim 6, in which saidmeans for driving drying air comprises a blower mounted under the plateand operative to drive the air therethrough.
 8. An arrangement accordingto claim 7, including a motor for driving said blower and said transportmeans.
 9. In a machine for making copies and including means forexposure of a copy sheet: means for development of the exposed copysheet; means for guiding the developed copy sheet to a receiving point;and means for directing air downwardly against the trailing end portionof said sheet to enhance stacking of the sheet at said receiving point.10. In a machine according to claim 9, a vertical plate portion overwhich the sheet is advanced to said receiving point, and generallydownwardly directed louvers in said plate portion through which the airis directed.
 11. In a machine for making copies and including means forexposure of a copy sheet; means for liquid development of the exposedcopy sheet; squeeze rollers operative to remove free liquid from thecopy sheet as it leaves the liquid development means and impelling thesheet toward a receiving point; means defining a guideway flaring fromsaid rollers generally downwardly and toward the discharge point; meansfor driving air through said guideway means onto a face of the sheet asit moves through the guideway; said guideway including a perforatedplate and said means for driving air driving the air through theperforated plate; said plate having louvers biased in the direction ofmovement of the sheet; said plate including a downwardly extendingportion at an end thereof remote from said rollers; and said downwardlyextending portion having generally downwardly directed louvers fordirecting air against trailing end of the sheet after it leaves saidplate.
 12. In a machine according to claim 11, an air blower under saidplate and driving the air through said louvers.